Thread-milling cutter



May 20, 1924. v 1,494,517

' H. c. WALTER \THREAD MILLING CUITER Filed July 51 1922 INVENTOR. HenryC. Walier ATTORNEY.

Patented May 2! 11924..

uni'ren srarss "was. I

HENRY c. WALTER, or isninenronlr, ocnnncrrcnr.

efficient than any of the same general type heretofore known whenconsidered from the standpoint of durability. speed-of production. andresults obtained,- the present cutter being capable of cutting a clean,deep thread when operating upon metal at a high rate of production.

i A. more specific object of the invention is to provide athread-milling-cutter equipped with cutter portions for producing threadhaving straight. tapering sides and toprovide eachcutterlportion withacutting edge on one side only thereof. y

A. further specific object is to arrange all of the cutting edges ofthey cutter portions so that .each is on a line which is radial withvrespect to the axis of the cutter to 39 operate inv a plane normal. tothe thread being out.

A. still further specific object to arrange the cutting edges oialternate cutter portions on the same sides of ithe cutter portions sothat one-half of "the cutting edges are at one sideotthe-thread-rnilling cutter and the other halt are at the opposite sidethereof.

. A still/further (t me to provide s thread-milling cutter theadvancinggtacesl or. sides of thecutter portions or -which; are obliqueor inclined to the axis of the cutter. to slant rearwardly from the.cutting edges of the cutter portions whereby the action of the cuttingedges is a shearing one. free from scraping.

,Yet a further object is ito provided a thread-milling cutter eachcutter portion of v 2 which. is provided with lone putting edge arrangedat one side of its forward or advancing face or surface.. said advancingface or surface slanting rearwardly from the cutting edge to be arrangedma ob liq'ue'angle to t he axis of the cutter. and.

the heel of each cutter'portion being re THREAD-MILLING CUTTER.

lieved bac of the'cutting edge to afford rleai'fance in passing throughathreadianril being planed or-cut down on its side opposite.thefcutting; edgeuto adord a chip space. I

And a further object is to provide a thread-milling cutter of disc formhaving cutter-portions the alternate ones of which are-climlicates ofeach other, every other cutter portion-having its cutting edgesitu:ated'at the same side o-fthe disc; aud'all of the cutter portions uponthe same side i of the] disc beingin alignment and having their cuttingedges posit-ioned radially with respeot to the axis of the-cutter andarranged at the same angle ,with respect vto the lengthof saidaxis,whereby the dupli cate rutt eri portions will accurately follow eachother whenmilling a thread.

All of the features ofthe novel thread milling cutter-cooperate in theaccomplishment of a -ll of the objects above enumerated. and tbe wholestructure lends itself to very efficient; service, each cutter portion-..l.)8l11{2 capable of use throughout the greater part of its width andthe structure. offering no interference to ready and accuratesharpeningof the cutter portions and. their cut ting edges, all'aswill'bgi hereinafter fully set forth. H a i Y .With the above objectsin view, as wellas others which will appear as the specificationproceeds. the invention: comprises the construction. arrangement andcombination ofparts [as now tobe-fully described and. as hereinafter tovbe specifically claimed. it being understood that the disclosure hereinis'merelyillustrative of the principles and meant to in no waylimitthespirit .ofthe invention, changes in. details of construction andarrangement of parts being per; missible solongas within the scope ofthe flrncnd dc ai a a a .In the'accompanying drawing forming a part ofthis specificatioln, 1 is an edge view of the novelthreadthecutterportions 13 being arranged at the other side of the body or discin alignment,

5 and each cutter portion 12, 13, respectively,

lying between cutter portions 13, 12. That is, all of the cutterportions 12, 13, are alternately arranged about the body.

As very clearly disclosed, each cutting edge 14. 15 of the diflerentcutter portions 12, 13, respectively, are on lines which are radial withthe axis of the thread-milling cutter, and the flat advancing faces orsides 16, 17 of the cutter portions 12, 13, respectively, carrying thecutting edges 14, 15, respectively, slant rearwardly from the cuttingedges to be situated at an oblique angle to the axis of the cutter.

The cutting edges 14, 15 extend, on a straight line, outwardly fromabout the neighborhood of the periphery of the body and toward thecenter of thickness of the body of the cutter. all of the cutting edgeshaving their inner and outer extremities,

respectively, terminating at equal. distances from the cutter axis. Thatis, all of the cutting edges have their inner extremities arranged onthe oppositely disposed faces of the body and thecutting edges 14 and 15converge, all of the cutting edges 14 terminating in a circumferencedenoted by'the outer extremity 18 of any cutting edge 14 and all of theextremities of the cutting edges 15 terminating in an equal circumference denoted by the outer extremity 19 of any cutting edge 15, theouter edge, denoted 20, of each cutter portion having about the samewidth as the outer edge of every other cutter portion, a widthpreferably much less than the'distance representing the thickness of thebod or disc. All of the cutting edges 14, 15, respectively, are arrangedat equal angles with respect to the length ofthe axis of the cutter andare in alignment about said axis, so that the cutting edges 14 will allaccurately follow each other and the cutting edges 15 will allaccurately follow each other to properly mill the straight, taperingsides of a thread.

Each cutter portion 12, 13 is relieved at 21, 22, respectively, back ofits cutting edge 14, 15, respectively, to afford clearance in pass ingthrough a thread, andeach cutter portion 12, 13 is planed or cut down asdenoted at 23, 24, respectively, opposite its cutting edge- 14, 15, toafford chip spaces, as will be understood.

All of the faces or sides 16, 17 of the cutter portions 12, 13 desirablyslant rearwardly from the cutting edges 14, 15, to make equal obliqueangles with respect to the axis of the cutter, whereas all of the facesor sides 16 slant in one direction and the faces or sides 17 slant inopposite direction, there being gashes between the cutter portions 12,13 and 13, 12 allowing for ready and accurate sharpening of the cutterfaces 16, 17 and their cuttingedges 14, 15. lilvidently, the width ofeach cutter portion is thus greatest. directly back of its cutting edge,the gash to the rear of each cutter portion slanting in a directionopposite that of the gash in front of the cutter portion and definingthe flat advancing face and cutting edge thereof. Consequently, thecutter portions can have extremely long life, the greater portion of thewidth of each being capable of use in cutting operations, until thecross-section of metal back of the cutting edge of each is worn so thatit cannot stand the strain.

By arranging each cutting edge on a line which is radial with respect tothe axis of the cutter all of the cutting edges operate in a planenormalto the thread being cut, and by arranging the advancing faces orsides of the cutter portions, carrying the cutting edges, to be obliqueor inclined to the axis of the cutter and to slant rearwardly from thecutting edges, the action of the cutting edges is a shearing one. It isunnecessary to remark that the advancing faces can have any suitable andpreferred slant. I have found that an arrangement of each advancing faceor side in a plane which is at an angle of twenty-two and one-halfdegrees to the axis of the thread-milling cutter is a satisfactoryarrangement for certain purposes and results.

Having thus fully described the invention, what I claim as new anddesire to secure by Letters Patent is:

1. A thread-milling cutter equipped with cutter portions each having atapering side and a straight cutting edge in advance of said side, theadvancing face of each cutter portion being adjacent said straightcutting edge and being inclined to the axis of the cutter to slantrearwardly therefrom, and the rearward face of each cutter portionslanting in a direction opposite that of the advancing face thereof sothat the width of each cutter portion is greatest directly back of itscutting edge. 4

2. A thread-milling cutter equipped with cut-ter portions each having aside arranged at an oblique angle with respect to said outter with astraight cutting edge in advance of said side, the advancing face ofeach cutter portion being adjacent said straight outting edge and beinginclinedto the axis of the cutter to slant rearwardly from said cuttingedge, and the cutter portions defining gashes about the periphery of thecutter and between the cutter portions,- the gash to the rear of eachcutter portion slanting in a direction opposite that of the gash infront thereof and defining the advancing face and,

cutting edge thereof, whereby the width of each cutter portion isgreatest directly back of its cutting edge.

3. A. thread-milling cutter equipped with cutter portions eachconstructed to produce thread having straight, tapering sides, eachcutter portion being provided on one side thereof with a straightcutting edge arranged at an oblique angle to the body of the cutter, andthe advancing face of each cutter portion being adjacent said straightcutting edge and being inclined to the axis of the cutter to slantrearwardly from said cutting edge, whereby gashes are provided about theperiphery of the cutter and between the cutter portions, the rearwardface of each gash being the advancing face of a cutter portion, and theforward face of each gash being the rearward face of each cutter portionand slanting in a direction opposite that of the advancing face of eachcutter portion, whereby the width of each cutter portion is greatestdirectly back of its cutting edge.

Signed at Bridgeport, in the county of Fairfield and State ofConnecticut, this 21st day of July, A. D., 1922.

HENRY C. WALTER.

